﻿#region BSD 3-Clause License
/* Copyright (c) 2012, Intel Corporation
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 * modification, are permitted provided that the following conditions are met:
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 * 1. Redistributions of source code must retain the above copyright notice, this
 *    list of conditions and the following disclaimer.
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 *    
 * 3. Neither the name of Intel Corporation nor the names of its contributors may
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 *
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#endregion

namespace OpenHopla.Numbers
{
    /// <remarks>
    /// An n-parasitic number (in base 10) is a positive natural number which can be
    /// multiplied by n by moving the rightmost digit of its decimal representation
    /// to the front. Here n is itself a single-digit positive natural number.
    /// See: http://en.wikipedia.org/wiki/Parasitic_number
    /// </remarks>
    public static class NumberTester
    {
        public static bool IsNParasiticNumber(long number, int digit)
        {
            if (number < 10)
            {
                return false;
            }
            else
            {
                string lastDigit = (number % 10).ToString();
                string prefix = (number / 10).ToString();
                string newNumberAsString = lastDigit + prefix;
                return ((long)(digit * number) == long.Parse(newNumberAsString));
            }
        }

        public static bool Is2ParasiticNumber(long number)
        {
            return IsNParasiticNumber(number, 2);
        }
    }
}
